Like the fact that they're only racing for one day?another insanely expensive unobtanium technology would be ceramic bearings. they might not even be made in sizes necessary for a car though or have enough load bearing capacity, but they do wonders for skateboards & bikes.
as to hydrogen filled tires, i guess i could see how tiny hydrogen atoms are more likely to leak than atmospheric oxygen, nitrogen & carbon dioxide, but refill every day? really? they never talk about long term issues like that in indy racing for some reason.